Ball joint stud



FIG. 1 is a side view of a ball joint stud showing my new design;

FIG. 2 is a top view of the ball joint stud thereof;

FIG. 3 is a bottom view of the ball joint stud thereof; and,

FIG. 4 is a sectional cut view, taken along line 4-4 of FIG. 1 , of the ball joint stud thereof. 

CLAIM The ornamental design for a ball joint stud, as shown and described. 